The unlicensed millimeter-wave (MMW) band of 57 GHz to 66 GHz has been distinguished as a highly promising candidate for high-data-rate short-range wireless communication utilizing the Institute of Electrical and Electronics Engineers (IEEE) 802.11ad standard, also referred to as WiGig, which employs frequencies of about 57 GHz to about 66 GHz). For example, broadband phased array systems are known that utilize antenna-in-package (AiP) for integrating MMW phased array planar antennas and associated radio-frequency (RF) components, together with base-band circuitry, into a complete self-contained module (e.g. USB dongle).
The performance of such antenna systems is dependent on the design and geometry of the surrounding enclosure or casing shell, particularly the radome that protects the antenna array. Non-optimal prior art enclosure shapes and antenna-to-enclosure distances are known to result in mm-wave signal distortions. The antenna main lobe is attenuated because of the loss characteristics of the radome material. Moreover, secondary radiation sources are formed because radio waves reflect off and are diffracted by non-transmissive surfaces and discontinuities in the enclosure. Surface waves are also diffracted from edges, slots, and corners. The secondary radiation sources and diffracted fields can be in-phase or out-of-phase with the main beam, giving rise to ripples in the antenna radiation pattern and power losses up to 4 dBm at some angles. Also, if the antenna is placed too far from the end of the enclosure, the illuminated area of the antenna is large, causing secondary out-of-phase radiation sources.
From the foregoing, it will be appreciated that there is a need for optimally designed enclosures for antenna systems that minimize one or more prior art disadvantages such as reduced antenna coverage, gain and radiation pattern degradation, EIRP (Equivalent Isotropically Radiated Power) level decrease, undesired beam tilt and undesired ripples and nulls in the radiation pattern that are characteristic of prior art short range and indoor wireless WiGig antenna systems.